As South Korea became the latest country to buy and deploy US F-35 stealth fighter jets, Chinese military observers asserted that an upgraded Chinese J-20 fighter will gain overwhelming superiority over the F-35 in future and that China can fend off all potential threats from what media dubs the “US F-35 friends circle” in the Asia-Pacific region.

Yonhap News Agency reported on Monday that two F-35As will be assigned to South Korean combat units starting in April or May. The delivery is a part of South Korea’s procurement of 40 F-35As in 2014 at a cost of more than $100 million each.

South Korea is not the only US ally that has purchased the stealth aircraft. Japan operates 10 F-35As, with 32 more due from a previous order, CNN reported in November 2018.

Japan is also preparing to order an additional 100 F-35 fighter jets. These aircraft include F-35Bs which are capable of short takeoffs and vertical landings, which will be deployed on the revamped Izumo-class helicopter destroyers, essentially making them aircraft carriers, Nikkei reported in November 2018.

Australia also received two F-35As in December 2018, local news site news.com.au reported. The country will eventually receive 100 of the jets, said the website of Australian Air Force.

Under the US’ Joint Strike Fighter program, the F-35 has three variations: the F-35A for the air force, the F-35B for marines and the F-35C for the navy.

By selling the stealth fighter jets to its allies in the West Pacific region, the US is building an “F-35 friend circle,” Wei Dongxu, a Beijing-based military analyst, told the Global Times on Tuesday.

The US, Japan and South Korea may conduct more joint exercises near China using the F-35, making it easy for coordination, Wei said. The stealth capability makes the F-35 more difficult to detect and will impact China’s national defense needs, he said.

Equipped with an advanced weapon system and capable of stealth and supersonic cruising, the F-35 is regarded as one of the most advanced fighter jets in the world. But China is no sitting duck in a potential clash with the US fighter jet.

China’s fifth generation fighter jet J-20, which has been in service under the People’s Liberation Army Air Force since early 2018, is endowed with state-of-the-art aviation and electronic technologies. Its range and weapons payload are widely considered to be better than the F-35’s, enabling it to achieve its main mission of gaining aerial superiority in a 21st Century battlefield.

Moreover, the J-20 has room for improvement. An upgraded version of the J-20 will have “overwhelming superiority” to the F-35 in the future, Wei said.

China’s passive radars and meter wave radars can also detect stealth aircraft, and can guide anti-aircraft missiles such as the HQ-9 and HQ-16 to destroy them, Wei noted.

Meanwhile, the F-35 has its share of problems.

The F-35’s stealth capability, one of the most important features that set it apart from previous generations of fighter jets, requires very high maintenance cost, as the radar wave-absorbing coating wears off and needs to be replaced after every flight, the news.com.au report said.

In September 2018, an F-35B under the US Marine Corps crashed due to faulty fuel-lines. F-35 jets have in the past made emergency landings, experienced in-flight incidents, including oxygen deprivation among crews, and suffered from engine fires and other failures on the ground, the Washington Post reported.